Message
Re: [QuadtoneRIP] Using log density measurements with the Linearize command
2017-07-24 by sanking@...
My assumption was that the density numbers should be entered as you note and that a correction curve with density numbers starting with the high density log measurements should be similar to a correction curve with lab values, inverted.
But sometimes this does not happen. I am including the .txt files of two profiles, one linearized with a spectro, the other with log density entries. When I run Install the one with lab values creates a good .quad file, but the one with density readings does not. If the lowest density readings is 0.00 the .quad files that is created is a straight line, similar to the original file with no linearization. If I enter a low density reading of 0.01, the .quad file is not created at all?
I have double checked my readings and entries and they look OK. Would appreciate your advice as to what I might be doing wrong.
Sandy
1. Linearize with lab values.
#PRINTER=Quad4880
#CURVE_NAME= Carbon100-230 #Based on Carbon Tissue #230, 14 grams of Black Cat Ink + 2 grams of Mixol #11, with tissue coated to a wet height of 0.9mm.
#Profile when printing a step wedge gives a DR (density range) of approximately log 2.05.
#With Tissue #230 sensitize with a 4% potassium dichromate solution, diluted 1+1 with acetone, approximately 10 ml per 8X10 sheet, applied in two coatings with a roller. 350 ULF units.
GRAPH_CURVE=YES
N_OF_INKS=8
DEFAULT_INK_LIMIT=100
LIMIT_K=25
LIMIT_C=1
LIMIT_M=1
LIMIT_Y=25
LIMIT_LC=1
LIMIT_LM=1
LIMIT_LK=50
LIMIT_LLK=1
GRAY_HIGHLIGHT=4
GRAY_SHADOW=4
GRAY_GAMMA= 1
CURVE_K= "0;0 100;100"
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=K
COPY_CURVE_LM=K
COPY_CURVE_LK=K
COPY_CURVE_LLK=K
LINEARIZE="25.36 30.5 34.58 37.29 40.37 43.36 45.96 48.44 50.99 53.52 56.41 59.24 61.36 64.34 67.25 69.62 72.48 76.31 83.55 89.9 96.74"
#LINEARIZE=“1.37 1.21 1.09 1.02 .95 .87 .82 .77 .72 .65 .60 .55 .50 .45 .41 .37 .33 .27 .16 .00”
2. Linearize with log density readings.
#PRINTER=Quad4880
#CURVE_NAME= Carbon100-230 #Based on Carbon Tissue #230, 14 grams of Black Cat Ink + 2 grams of Mixol #11, with tissue coated to a wet height of 0.9mm.
#Profile when printing a step wedge gives a DR (density range) of approximately log 2.05.
#With Tissue #230 sensitize with a 4% potassium dichromate solution, diluted 1+1 with acetone, approximately 10 ml per 8X10 sheet, applied in two coatings with a roller. 350 ULF units.
GRAPH_CURVE=YES
N_OF_INKS=8
DEFAULT_INK_LIMIT=100
LIMIT_K=25
LIMIT_C=1
LIMIT_M=1
LIMIT_Y=25
LIMIT_LC=1
LIMIT_LM=1
LIMIT_LK=50
LIMIT_LLK=1
GRAY_HIGHLIGHT=4
GRAY_SHADOW=4
GRAY_GAMMA= 1
CURVE_K= "0;0 100;100"
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=K
COPY_CURVE_LM=K
COPY_CURVE_LK=K
COPY_CURVE_LLK=K
#LINEARIZE="25.36 30.5 34.58 37.29 40.37 43.36 45.96 48.44 50.99 53.52 56.41 59.24 61.36 64.34 67.25 69.62 72.48 76.31 83.55 89.9 96.74"
LINEARIZE=“1.37 1.21 1.09 1.02 .95 .87 .82 .77 .72 .65 .60 .55 .50 .45 .41 .37 .33 .27 .16 .07 .00”